Umbilical Cord Prolapse, UCP

1. What every clinician should know

Umbilical cord prolapse is an obstetric emergency, with an overall incidence of 1.4-6.2 per 1000 deliveries.

It occurs when the membranes rupture and the umbilical cord passes into the internal os in front or along the side of the presenting part of the fetus. Compression of the umbilical cord results in reduction in blood flow to the fetus, which, when uncorrected, can result in fetal organ damage or demise.

Rapid mobilization of the obstetrical team, maneuvers to relieve the umbilical cord compression, and rapid delivery of the infant are required.

Two types of umbilical cord prolapse can occur. The "overt prolapse" is the more obvious case where the umbilical cord is prolapsed thru the os into the vaginal canal (Figure 1). The "occult prolapse" occurs where the umbilical cord is below or next to a fetal presenting part and may not be visible or palpated in the cervical or vagina (Figure 2). In either case, fetal heart rate decelerations may be prolonged and severe, necessitating a rapid delivery.

2. Diagnosis and differential diagnosis

Diagnosis

Funic presentation: An umbilical cord leading into the internal os or cervical canal (funic presentation) can be visualized on ultrasound and typically confirmed by using color or power Doppler. If identified in early pregnancy, it is frequently displaced later in the pregnancy by the larger presenting part of the fetus. Repeat ultrasound later in gestation or at the time of labor is required to exclude persistent funic presentation. If identified in the late third trimester, particularly after the onset of labor, it is unlikely to resolve.

Whenever a funic presentation is identified, it is important to exclude a vasa previa. Identifying the cord insertion into the placental disc using color or power Doppler excludes a vasa previa, unless there is a succenturiate placenta. Identifying fetal vessels coursing along the uterine wall or over the internal os raises the suspicion of a velamentous cord insertion or vasa previa, respectively. Transvaginal ultrasound is the best approach to identify and confirm a funic presentation or vasa previa. A persistent funic presentation is an indication for cesarean delivery.

The fetal head will typically descend through the pelvic inlet before or early in labor. In the case of a contracted pelvis, the fetal head may never properly descend and remains "floating." This will increase the risk for umbilical cord prolapse. An adequate pelvic inlet can be estimated by the use of the diagonal conjugate, with a diameter less than 11.5 cm suggesting a contracted pelvis.

A high index of suspicion should be maintained whenever risk factors have been diagnosed during the pregnancy, particularly in women with preterm premature rupture of membranes managed expectantly or following rupture of the membranes in women who have an unengaged fetal presenting part or malpresentation (particularly transverse lie or footling breech). Variable or prolonged fetal heart rate decelerations in the presence of risk factors should raise the suspicion for cord prolapse.

Amniotomy should not be performed unless the fetal presenting part is well applied on the cervix, although an engaged and well-applied presenting part is not a guarantee that cord prolapse, particularly the occult type, will not occur as the presenting part may still move away.

Certain intrapartum interventions that require elevation of the presenting part, such as the use of an intrauterine pressure catheter or manual rotation of the fetal head, may result in cord prolapse. Correspondingly, examination for the presence of a cord should be performed at the completion of these intereventions and before leaving the patient's bedside. The fetal heart should be monitored continuously after amniotomy or after any of these procedures, and a pelvic examination should be performed if decelerations are noted.

In two-thirds of cases, the first indication of umbilical cord prolapse is fetal heart deceleration of rapid onset, and may include prolonged bradycardia or repetitive severe variables. In the case of overt cord prolapse, immediate examination of the vaginal vault will reveal a soft pulsatile mass. In some cases, the cord may be visible and protruding at the introitus.

In the case of occult cord prolapse, the umbilical cord cannot be palpated in the vagina or cervix. Obstetric care will be guided by the degree of the fetal heart rate decelerations and location of the umbilical cord.

Differential Diagnosis

There are very few conditions that may mimic a prolapsed cord and the list of differential diagnoses is short. Feeling a pulsatile cord in the vagina or cervix is unmistakable.

Similarly, fetal heart rate decelerations are not always associated with cord prolapse and other reasons for a fetal heart rate should be considered.

A nonpulsatile mass in the vagina must be differentiated from a fetal limb other fetal part.

3. Management

Antepartum: LIttle can be done in the antepartum period to prevent umbilical cord prolapse.

Intrapartum: Diagnosis of an overt umbilical cord prolapse is an obstetric emergency. Initiate a team alert and obtain extra help at the bedside. Immediate goals are relief of umbilical cord compression and delivery of the infant. Avoid excessive palpation of the prolapsed cord segment as this can cause vasospasm, further contributing to fetal heart rate decelerations.

Place the entire hand in the vaginal vault and gently elevate the presenting fetal part so it no longer compresses the umbilical cord.

Positioning of the mother is another important management approach. In some instances of occult cord prolapse, turning the patient to one side or the other may relieve some of the cord compression. With overt prolapse, the patient may be put in the knee-chest position while the presenting part is elevated and preparations for delivery are under way. Elevation of the presenting part should be maintained until delivery is accomplished (Figure 3).

Figure 3.

Positioning of the mother.

Urgent delivery is recommended most often via urgent cesarean section. In rare cases, a vaginal delivery, either spontaneous or operative, may be achieved more rapidly than a cesarean delivery. This should be guided by the degree of cord compression (inferred from the severity of fetal heart rate decelerations) and the relative time it would take to perform a cesarean versus a vaginal delivery. In case of a cord prolapse during the delivery of the second twin, an operative vaginal delivery, breech extraction, or internal podalic version followed by breech extraction can be accomplished faster than a cesarean delivery, granted that the attendant has the necessary skills.

If the umbilical cord prolapse occurs in a location remote from an operating suite, the above maneuvers are still needed but in addition, the maternal bladder can be filled with 500-750 mL normal saline via a Foley catheter, which is then clamped. Distending the bladder in this manner provides upward pressure on the fetal presenting part and relieves compression of the prolapsed cord segment while further preparations for delivery are undertaken.

Replacing the prolapsed segment of umbilical cord into the uterus has been described in cases when the umbilical cord in barely felt through the internal os. When attempted, concurrent preparations for cesarean delivery should be initiated in order to avoid delay should replacement be unsuccessful. Although there are few reports of success, historically poor neonatal outcome and demise are noted and thus, except for extreme cases, this cannot be recommended.

Expectant management (i.e., no emergent delivery) should be considered when there is a fetal demise, anomalies incompatible with life, or the fetus is not at a gestational age consistent with ex utero survival.

4. Complications

5. Prognosis and outcome

Rapid diagnosis and performance of maneuvers to decrease the compression of the prolapsed umbilical cord have resulted in good outcome for both the mother and infant, particularly in centers possessing the ability to perform urgent cesarean delivery.

Prognosis is usually dependent on the status of the fetus at the time of the prolapse, the degree of cord compression, and the time from occurrence to delivery.

6. What is the evidence for specific management and treatment recommendations

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